Pure or mixed monocrystalline boules of lanthanum orthogallate

Abstract

Monocrystalline lanthanum orthogallate compositions grown along a predetermined crystallographic direction in the form of a single crystal of a size greater than 1 cm in diameter/width and at least 10 cm in length are described. Such compositions include mixed crystal monocrystalline lanthanum orthogallates wherein a portion of the lanthanum is replaced with a rare earth element of smaller ionic radius than lanthanum and/or a portion of the gallium is replaced with Al, Sc or In. The foregoing monocrystalline compositions are particularly suited as superconductor substrates.

We claim: 
     
       1. Monocrystalline lanthanum orthogallate in either pure or mixed crystal form grown from a pure melt along a predetermined crystallographic direction; said monocrystalline lanthanum orthogallate being in the form of a single crystal having dimensions greater than 1 cm in diameter and 10 cm in length. 
     
     
       2. The monocrystalline lanthanum orthogallate of claim 1, further characterized in that the lanthanum orthogallate crystal is a mixed crystal lanthanum orthogallate wherein a portion of the Ga is replaced with Sc, Al or In. 
     
     
       3. The monocrystalline lanthanum orthogallate of claim 1, further characterized in that the lanthanum orthogallate crystal is a mixed crystal lanthanum orthogallate wherein a portion of the lanthanum is replaced with a rare earth element of smaller ionic radius than lanthanum, said mixed crystal lanthanum orthogallate being characterized by the formula R x  La 1-x  GaO 3  wherein R is a rare earth element of smaller ionic radius than La and wherein x=0.001 to 0.5. 
     
     
       4. The monocrystalline lanthanum orthogallate of claim 1, further characterized in that the lanthanum orthogallate crystal is a mixed crystal lanthanum orthogallate wherein a portion of the lanthanum orthogallate is replaced with a rare earth element of smaller ionic radius than La and wherein a portion of the Ga is replaced with Al, said crystal lanthanum orthogallate being characterized by the formula R x  La 1-x  Ga 1-y  Al y  O 3  wherein R is a rare earth element of smaller ionic radius than La and wherein x and y are the same or different and have a value of from 0.001 to 0.5. 
     
     
       5. The monocrystalline lanthanum orthogallate of claim 1, further characterized in that the lanthanum orthogallate crystal is a mixed crystal lanthanum orthogallate wherein a portion of the lanthanum orthogallate is replaced with a rare earth element of smaller ionic radius than La, wherein a portion of the Ga is replaced with Sc, said crystal lanthanum orthogallate being characterized by the formula R x  La 1-x  Ga 1-y  Sc y  O 3  wherein R is a rare earth element of smaller ionic radius than La and wherein x and y are the same or different and have a value of from 0.001 to 0.5. 
     
     
       6. The monocrystalline lanthanum orthogallate of claim 1, further characterized in that the lanthanum orthogallate crystal is a mixed crystal lanthanum orthogallate wherein a portion of the lanthanum orthogallate is replaced with a rare earth element of smaller ionic radius than La, wherein a portion of the Ga is replaced with In, said crystal lanthanum orthogallate being characterized by the formula R x  La 1-x  Ga 1-y  In y  O 3  wherein R is a rare earth element of smaller ionic radius than La and wherein x and y are the same or different and have a value of from 0.001 to 0.5. 
     
     
       7. The mixed crystal monocrystalline lanthanum orthogallate of claim 2, further characterized by the formula La Ga 1-x  Sc x  O 3  wherein x=0.001-0.5. 
     
     
       8. The mixed crystal monocrystalline lanthanum orthogallate of claim 2, further characterized by the formula La Ga 1-x  Al x  O 3  wherein x=0.001-0.5. 
     
     
       9. The mixed crystal monocrystalline lanthanum orthogallate of claim 33, further characterized by the formula La Ga 1-x  In x  O 3  wherein x=0.001-0.5. 
     
     
       10. The monocrystalline composition of claim 3, wherein x=0.01-0.2. 
     
     
       11. The monocrystalline composition of claim 3 wherein R is Y. 
     
     
       12. The monocrystalline composition of claim 4, wherein x=0.01-0.2. 
     
     
       13. The monocrystalline composition of claim 4 wherein R is Y. 
     
     
       14. The monocrystalline composition of claim 5, wherein x=0.01-0.2. 
     
     
       15. The monocrystalline composition of claim 5 wherein R is Y. 
     
     
       16. The monocrystalline composition of claim 6 wherein x=0.01-0.2. 
     
     
       17. The monocrystalline composition of claim 6 wherein R is Y. 
     
     
       18. The monocrystalline composition of claim 7, wherein x=0.01-0.2. 
     
     
       19. The monocrystalline composition of claim 8, wherein x=0.01-0.2. 
     
     
       20. The monocrystalline composition of claim 9, wherein x=0.01-0.2. 
     
     
       21. The monocrystalline composition of claim 11 wherein x=0.01-0.2. 
     
     
       22. The monocrystalline composition of claim 13 wherein x=0.01-0.2. 
     
     
       23. The monocrystalline composition of claim 15 wherein x=0.01-0.2. 
     
     
       24. The monocrystalline composition of claim 17 wherein x=0.01-0.2.